A Randomized Trial of Laser-assisted Uvulopalatoplasty in the Treatment of Mild Obstructive Sleep Apnea

Departments of Medicine and Otolaryngology, University of Western Ontario, London, Ontario, Canada

	ABSTRACT

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION REFERENCES

 
Laser-assisted uvulopalatoplasty (LAUP) is an outpatient surgical treatment for snoring and obstructive sleep apnea (OSA), but to date, no controlled trials have been published. Forty-five subjects with mild OSA (apnea/hypopnea index , 10–27 per hour) were randomized to LAUP or to no treatment (control group). The AHI post-LAUP was reduced by 21% overall and to 10 or less per hour in 5 of 21 subjects (24%). Four of 24 subjects in the control group (16.7%) had an AHI of 10 or less per hour at outcome. The AHI decreased with the LAUP compared with no change with the control group at outcome. Ten subjects (48%) reported significantly improved snoring after the LAUP. There was no improvement in excessive daytime sleepiness, but there was a small improvement in quality of life (unless side effects were included in the quality of life score). Side effects were common, but serious complications did not occur. LAUP surgery is effective in some subjects with mild OSA for the treatment of snoring, but the reduction in AHI and the level of symptomatic improvement were minor overall.

　

Key Words: obstructive sleep apnea • randomized trial • laser surgery • laser-assisted uvulopalatoplasty

	INTRODUCTION

TOP BSTRACT INTRODUCTION METHODS RESULTS DISCUSSION REFERENCES

 
There are a number of options for the treatment of snoring and obstructive sleep apnea (OSA). Patients with moderate to severe OSA are usually treated with nasal continuous positive airway pressure (1). Although continuous positive airway pressure eliminates apnea in virtually all cases, there are problems with patient acceptance of continuous positive airway pressure therapy, particularly in patients with mild OSA. Oral appliances are safe and reasonably effective in patients with mild OSA, but they also represent a control and not a cure (2, 3). Patients who desire a cure for their problem generally look to surgical treatment. The two most common surgical procedures are uvulopalatopharyngoplasty (UPPP) and laser-assisted uvulopalatoplasty (LAUP).

Kamami developed the LAUP procedure as an alternative to UPPP (4). He first used it in patients who complained of snoring after UPPP and who still had residual vibrating tissue on their soft palate (5). Subsequently, the procedure was expanded to patients who wanted their snoring treated without undergoing a major procedure under general anesthesia. Despite its widespread use, LAUP has not been established as an effective therapy for OSA in the setting of controlled clinical trials, and in uncontrolled trials, the results are variable (6). Many clinicians and patients are convinced of its effectiveness in relieving snoring based on their personal experience, but rarely is treatment success objectively documented. A published guideline focused on the lack of controlled studies and recommended that patients should be told that the risks, benefits, and complications of the procedure are not known (7). In an update published in 2000, the authors stated that no controlled trials were found in the peer-reviewed literature, and they recommended that LAUP not be done for the treatment of OSA (8). However, it could be used for the treatment of snoring. In general, the studies published to date have been retrospective case series or prospective precomparisons and postcomparisons without control groups and often with incomplete follow-up. Problems with many of these studies include poorly detailed methods and selection criteria, inadequate overnight monitoring (before and after surgery), mainly subjective follow-up, and incompletely defined outcome criteria. Other deficiencies of this literature have been well described previously (9).

The objective of this study was to determine with a randomized, controlled trial the efficacy of LAUP in relieving OSA in patients with mild symptomatic sleep apnea. The secondary objectives were to determine the effect of LAUP on symptoms of OSA, including snoring, daytime sleepiness, and quality of life.

	METHODS

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Forty-five subjects who had mild OSA (apnea/hypopnea index , 10.1–25) and complained of loud snoring were recruited. Weight, body mass index, blood pressure, and neck circumference were recorded at baseline. A detailed questionnaire was administered along with the Epworth Sleepiness Scale (10) and the Calgary Sleep Apnea Quality of Life Index (SAQLI) (11). The five domains of the SAQLI include domain A daily functioning, domain B social interactions, domain C emotional functioning, domain D symptoms, and domain E treatment-related symptoms (side effects and complications). Snoring intensity and frequency were rated on a modified four-point Likert Scale (never, softly, moderately, loudly and never, rarely, sometimes, often respectively). The bed partner or household member rated snoring intensity (0 = none to 10 = loud) and frequency (0 = never to 10 = always) with a visual analog scale.

Using a table of random numbers, subjects were randomized to either the LAUP group or the no-treatment group (control group). The control subjects were not offered any therapy but were offered LAUP at the end of the study. Questionnaires, scales, and the polysomnogram were repeated 3 months after the last LAUP procedure or 6 months after baseline in the control group. The frequency and severity of treatment side effects and complications in the LAUP group were recorded.

Overnight Polysomnography
A standard montage was used for polysomnography, including electroencephalogram, electro-oculogram, submental electromyogram, left and right anterior tibialis electromyogram, electrocardiogram, thoracoabdominal motion, oronasal airflow (thermistor), and arterial oxygen saturation with pulse oximetry. Obstructive apneas were defined as the cessation of airflow for at least 10 seconds accompanied by ongoing respiratory effort. Obstructive hypopneas were defined as a reduction in airflow of at least 50% for at least 10 seconds accompanied by a reduction in respiratory effort. Events were associated with an arousal and/or an oxygen desaturation of 3% and/or an associated period of bradycardia/tachycardia.

LAUP Procedure
The LAUP procedure was repeated at 1- to 2-month intervals. The end points for the LAUP procedure were (1) when the snoring was reported to be significantly reduced or eliminated, (2) no more tissue could be safely removed, or (3) the patient refused further surgery.

Subjects received preoperative pain medication. Topical anesthesia was applied liberally, and lidocaine was injected into the uvula and soft palate. A series of full-thickness vertical trenches were created with the CO₂ laser on the free edge of the soft palate on either side of the uvula. The uvula was shortened and thinned to a fraction of its former size. The edge of the soft palate was also reduced. The tonsils were not treated. A backstop on the laser attachment was used to prevent injury to the posterior pharyngeal wall. The laser was activated during exhalation, and suction was used to remove the smoke from the surgical field. Subjects received postoperative antibiotics, analgesics, antiinflammatories and dilute hydrogen peroxide gargles for 7 days.

Outcome Measurements
The primary outcome measurement was the reduction in AHI in the LAUP group versus the control group. Treatment success was defined as a reduction in AHI to 10 or less per hour. Treatment failure was defined as an inadequate reduction in AHI (post-treatment AHI of more than 10 per hour). A complete response was defined as a reduction in AHI to 10 or less per hour along with a satisfactory symptomatic response (as determined by the patient). Subjective outcomes included snoring frequency and severity, change in symptoms (e.g., excessive daytime sleepiness), and quality of life.

The sample size was calculated with data from published studies of LAUP (12–16). The study had a 90% power to detect a 25% reduction in AHI in the treatment group compared with no reduction in AHI in the control group with an